Here's what we know so far about Trump's climate change plans

What does President Donald Trump think about climate change, and what does he plan to do about it? Over the course of his long public life, Trump has held a range of opinions, many of them contradictory. Here’s what we know:

In 2009, Trump, along with many other business leaders, signed an open letter to President Barack Obama and Congress asking them to "strengthen and pass U.S. legislation and lead the world by example." The letter called climate change "an immediate challenge facing the United States and the world today" and called global warming "scientifically irrefutable." Three of Trump’s children — Donald Jr., Eric and Ivanka — also signed the letter.

The open letter, published in the New York Times on Dec. 6, 2009, coincided with a meeting to address climate change in Copenhagen attended by Obama and other world leaders. According to Grist, which found the letter in June;

None of the signers that Grist interviewed this week could recall who had organized the letter or knew who had asked Trump to sign. The website of the group listed on the ad, businessleaders4environmentalchange.us, is now defunct, and no information was available on who had registered it.

By 2010, however, Trump had seemingly changed his mind. Weeks before Obama and other world leaders met in Copenhagen, hackers published a series of emails between climate change researchers from the University of East Anglia. Climate change skeptics latched onto the emails, which they claimed showed the researchers had manipulated climate change data. Eight independent investigations — three in the U.K. and five in the U.S. — found no such thing happened, but Trump touted the scandal, dubbed "Climategate," on Fox News. "I guess they’re saying it’s a con," Trump told Fox’s Neil Cavuto, of climate change.

Trump's views moved further right as Obama’s presidency continued. In 2012, Trump tweeted that global warming was invented by China for the benefit of Chinese companies. In 2013, he called it “a total, and very expensive, hoax."

Trump has claimed global warming is "fictional" and "bullshit" and has repeatedly cited cold weather as evidence that climate change isn’t real.

"It's really cold outside, they are calling it a major freeze, weeks ahead of normal," Trump said in one tweet. "Man, we could use a big fat dose of global warming!"

After his election in November, Trump appeared to be warming to the scientific consensus. In an interview with the New York Times, Trump said he had an "open mind" about climate change, but repeated false claims about Climategate, and other claims pushed by climate change deniers. For instance, Trump said, "I’m not sure anybody is ever really going to know" the truth about climate change, when, in fact, 97% of scientists agree that it’s both real and likely caused by human activity.

Trump has also reversed many Obama-era policies aimed at curbing greenhouse gas emissions. Trump issued memos approving the Keystone XL and Dakota Access pipelines, which environmentalists say could endanger animals that live in areas bisected by the pipelines. Climate change researchers have also said the pipelines, which would deliver 830,000 barrels of crude oil per day, could increase the U.S.'s reliance on fossil fuels, which contribute to climate change.

Trump has also said he wants to dismantle the Paris climate agreement, which was signed by nearly 200 countries in an effort to curb greenhouse gas emissions — though after the election he said he had an "open mind" about the accord. And Secretary of State Rex Tillerson said during the confirmation process that he backs the agreement.

Trump's Cabinet, though is a decidedly mixed bag. Trump nominated Oklahoma Attorney General Scott Pruitt, a climate change denier, to lead the Environmental Protection Agency.

"It’s a safe assumption that Pruitt could be the most hostile EPA administrator toward clean air and safe drinking water in history,” Ken Cook, head of the Environmental Working Group, told the New York Times.